When performing surgery on the brain, it is often necessary to perform a craniotomy to provide access to portions of the brain. A craniotomy is a surgical procedure in which a portion of the cranial vault is removed to permit access to the brain. To perform the craniotomy, several burr holes are initially drilled through the skull. A saw is then used to cut the skull along the line of separation connecting the adjoining burr holes, i.e., a craniotomy is performed. The resulting bone cover or cranial flap is subsequently lifted from the underlying dura mater to expose the brain. The bone cover may either be completely removed from the cranium, or folded back on a muscular and/or aponeurotic hinge.
After completion of the procedure on the brain, the bone cover must be re-attached to the skull using either non-resorbable sutures, and more recently using devices that have been developed to help secure the bone cover to the skull such as cranial clamp. See, for example, U.S. Pat. No. 6,258,091 to Sevrain et al., U.S. Pat. No. 6,589,244 to Sevrain et al., U.S. Pat. No. 5,707,373 to Sevrain et al., and U.S. Pat. No. 6,685,707 to Roman et al. (all of which are incorporated by reference herein in their entirety). These fasteners (Rapid Flap™—Walter Lorenz Surgical— or CranioFix™—Aesculap, Stryker—) allow a fast, secure and anatomical repositioning of the bone cover, but realize a rigid fixation which forbids movement of the flap, especially during the post-operative course when a brain swelling may occur.
This inability to expand in case of post-operative swelling can be harmful to the brain in damaging cerebral tissues due to the increase of intracranial pressure (ICP). Similarly, these rigid fixations cannot be used when a decompressive craniotomy (to relieve cerebral edema and intracranial hyperpression following a traumatic brain injury) is performed. Therefore, a dynamic fixation allowing the flap to accommodate swelling while still aligning properly for healing would be desirable.